Various photosensitive lithographic printing plates requiring no fountain solution (hereinafter referred to as "waterless lithographic printing plate") for lithographic printing without fountain solution have been proposed. Among them, those comprising a photosensitive layer and a silicone rubber layer coated on a support in this order as disclosed in JP-B-54-26923 (The term "JP-B" as used herein means an "examined Japanese patent publication"), JP-B-55-22781, JP-B-56-23150, and JP-A-2-236550 (The term "JP-A" as used herein means an "unexamined published Japanese patent application") have extremely high performances.
As a process for the development of such a waterless lithographic printing plate, there is a process which comprises developing the plate by the use of a hydrocarbonic organic solvent which swells only a silicone rubber layer or a hydrocarbonic organic solvent with a polar solvent added thereto, and then dyeing it, as disclosed in JP-B-56-23150, JP-A-57-13448, JP-A-59-146054, and JP-A-63-52145. However, this process requires a long development time. In order to obtain fine halftone dots on the highlight with a good reproducibility, it is necessary that the printing plate be brushed to a certain extent. Accordingly, this process is disadvantageous in that even the silicone rubber layer to be left as non-image area can be damaged. On the other hand, JP-B-63-46407 discloses a process which comprises eluting a part or whole of the photosensitive layer on the image area with a processing solution capable of dissolving at least a part of the photosensitive layer on the image area, and then rubbing the printing plate in the presence of water or a solvent mainly composed of water which doesn't swell the silicone rubber layer to peel off the silicone rubber layer. Further, JP-A-1-159644 and JP-A-3-231752 disclose a developer comprising water as a main component. These approaches can provide drastic reduction of damage of the silicone rubber layer on the non-image area during development but leave much to be desired in the prevention of damage on the silicone rubber layer in handling and printing after processing.
In order to solve the foregoing problems, an approach has been proposed which comprises, after the development with an aqueous developer for removing substantially only the silicone rubber layer on the unexposed area, the dyeing with a dye solution containing a difficultly water-soluble compound, so that the non-image area can be plasticized by the difficultly water-soluble compound, enhancing the scratch resistance of the waterless lithographic printing plate thus processed.
However, this approach is disadvantageous in that when the printing plate thus dyed is rinsed, precipitation occurs. Further, the silicone rubber layer on the nonimage area or the back side of the support is stained. When the dye tank is drained and rinsed, precipitates are produced and attached to the tank, roller and filter, interrupting the rinsing.
JP-A-3-129350 discloses a dye solution comprising a nonionic surface active agent. However, such a dye solution comprising a nonionic surface active agent is disadvantageous in that when the processing is effected with such a dye solution in an automatic developing/dyeing machine equipped with a brush roller in the development and dyeing zones, remarkable foaming occurs.